Right angle connectors



p 8, 1970 A. R. BRISHKA 3,528,052

ANGLE 0 N C CR5 Filed May 15, 1968 RIGHT C N E T 2 Sheets-Sheet. 1

42 27 FIG. 1 F 48 P3 64 ALEXANDER R. BRISKA 62 a INVENTOR.

JOHN P CHANDLER HIS ATTORNEY.

United States Patent 3,528,052 RIGHT ANGLE CONNECTORS Alexander R.Brishka, 14 Sophia St., Mamaroneck, N.Y. 10543 Continuation-impart ofapplication Ser. No. 659,729,

Aug. 10, 1967. This application May 13, 1968,

Ser. No. 728,648

Int. Cl. H01r 17/18 US. Cl. 339177 4 Claims ABSTRACT OF THE DISCLOSURE Aright angle coupling for high frequency concentric lines includes aconductive housing having coupling means at either end. An air cavityadjoining a bend in the insulation on the central conductor corrects fora bad impedance match and reduces wave reflection.

This application is a continuation-in-part of my copending applicationSer. No. 659,729, filed Aug. 10, 1967, and now Pat. No. 3,432,798.

This invention relates to angular electrical connectors and moreparticularly to right angle coupling units used for high frequencysignals.

An object of the present invention is to provide an angular connectorfor concentric lines having improved electrical characteristics. Anotherobject is to provide an improved right angle connector which eliminates,as far as possible, impedance discontinunities and thereby excludes wavereflections at the connector.

The usual practice in forming angular or elbow connectors has been touse a two piece contact and insulator design to form the right angle andthen solder the two straight contacts together. The cavity surroundingthe joint is then filled with insulating material, or the cavity may beleft unfilled with air acting as the dielectric. This device gives poorelectrical performance due primarily to the varying relationshipsbetween the outer diameter of the inner conductor and the inner diameterof the outer conductor.

The present invention provides a right angle connector with the usualcylindrical insulation provided for the concentric line. At the portionof the line where both the inner conductor and its cylindricalinsulation covering are bent at an angle, the outer covering is alwaysstretched to a considerable degree and for this reason its thickness isreduced, thereby changing the impedance of the line, and introducingwave reflections. An attempt has been made to solve this difliculty bypacking finely divided conductive material around the bend and therebysimulate a continuous outer conductive coating. This means, whileeliminating part of the trouble, does not completely solve the problembecause the conductive material is then closer to the inner conductordue to the fact that the insulation has been diminished at this point.One method of eliminating this discontinuity is to omit the finelydivided material but provide an enclosing conductive structure filledwith air as the dielectric insulating covering. This type of structuregenerally overcompensates for the change in impedance and, to produce anonreflective coupling, a portion of the conductive plating and some ofthe insulation at the bend is removed by means of a file or othercutting tool. Still another compensating means is to provide a similarenclosing structure and insert a conductive filler next to the reducedinsulation. The portion of this conductive filter and/ or plating whichis adjacent to the bend must be hollowed out and/ or removed at the apexof the bend so that a variable air space is supplied to that portion ofthe line.

3,528,052 Patented Sept. 8, 1970 ice In the drawings:

FIG. 1 is a central longitudinal cross section taken through a rightangle connector embodying one form of the invention;

FIG. 2 is a cross sectional view of the connector shown in FIG. 1 and istaken along line 22 of that figure;

FIG. 3 is a cross sectional view of the connector shown in FIG. 1 and istaken along line 3-3 of that figure;

FIG. 4 is a cross sectional view of a portion of the connector shown inFIG. 1. This view shows a conductive insert having a cut-out portionwhich produces a variable air gap;

FIG. 5 is a graph showing the approximate directions of the lines offorce in the electric field when a portion of the plating has beenremoved from the insulator and there is no adjoining conductor.

The right angle connector shown in FIG. 1 employs a single contactconductor of substantially the same diameter as the central conductor 11of a coaxial cable 12, the contact being enclosed in an insulatingsleeve 14. The insulating sleeve 14, enclosed in conductive portions 27and 69 of the coupling components, forms an adequate outer conductor fora wide range of high frequencies without serious power loss. However,when the transmitted power frequency is above 10 Hz., the losses areexcessive and it has been found necessary to surround the insulatingsleeve in the region of the bend with conductive particles or plating ora combination of both in order to provide a continuous conductive pathbetween portions 27 and 69. The plating may be either silver or gold orsome other metal.

One end of the contact 10 may have a reduced or rounded terminal section18 which is received in force fit relationship in a female Contacthaving a solid central section 19, a slotted bore 20 to receive thecontact and a bore 22 at its other end to receive the central conductor11. Section 19 is surrounded by a cylindrical insulator 14A. The wall ofbore 22 may have an opening for outgasing purposes as well as to receivea drop of solder shown at 24. The other end section of the contact isrounded and is of reduced diameter near its end 26 in order to bereceived in a female contact (not shown) for connection with anothercoaxial cable.

A tubular body 27 receives one end of the insulated right angularcontact and, at one end, it has a bore 28 for receiving one end of theinsulated covering 14. The inner end of bore 28 is chamfered at the endof the bore to facilitate the entry of the insulated contact. Thesection of the tubular body 27 adjacent to the end of the centralcontact 10 is enlarged slightly as indicated at 30 and an additionalenlarged bore indicated at 31 is provided for an insulating washer 33positioned adjoining to a metal bushing 32. A similar metal bushing 34is positioned on the other side of washer 33 and these three units areclamped into place by a short length of pipe having threads which meshwith internal threads on body 27 and a wrench receiving extension 42 forscrewing into place. The washer 34 is formed with slotted wedge-likeprojections 36 which fit against a tapered section 38 of the internalsurface of the pipe 42 and thereby facilitates a close fitting betweenthe body 27 and the external surface of conduit 12. The opposite end ofthis body member 27 has a reduced threaded section 46 which receives asleeve 48 internally threaded to receive section 46. Sleeve 48 is alsointernally threaded at its other end 52 to receive a closure plug 54.The lower portion of sleeve 48, when viewed as in the drawing, has athreaded hole 56 to receive a reduced threaded terminal 58 of a tubularbody whose axis is at right angles to the major axis of body member 27and has an upper flange which is screwed tight against its adjoiningportion of member 27.

A coupling nut 63 is formed with a wrench receiving surface 62 and isconnected to body 58 by a split locking ring 64 positioned in alignedannular slots formed in members 58 and 62. Body 58 has a bore 69 of suchsize as to receive the insulation 14 of the contact in snug fit. Asealing gasket 66 is positioned in a recess 70 near the outer end ofbody 58, thus providing a seal between the body 58 and its coupling nut63. An internal thread 71 is provided on the inside portion of the nut63 for connection to another coupling unit.

When bending the conductive portion 10 at right angles the outerinsulation, which may be Teflon, is elongated and for this reason itsthickness is reduced. In FIG. 1, the normal extent of the insulation isshown by dotted line 73. Since there is always a reduction in thickness,a compensation means must be pr vided to maintain substantially constantimpedance along all portions of the line. The conductive plating 15 isremoved from this part of the insulation and the hollow portion 74within the sleeve 48 is used to provide this compensation because thedistance between the center conductor and the surfaces of cavity 74 isgreater than the distance between the center conductor and the platingadjacent to the exposed Teflon insulating material. The sleeve 48 andthe plug 54 are both conductive and the air portion inside cavity 74acts as additional insulation which is added to that portion of theTeflon insulating 14 adjoining it. The electrical field lines existingin the region of the removed plating will terminate on the outerconducting surface of the plating in the immediate vicinity of theunplated portion of the insulating material as shown in FIG.5. Theincrease in the length of the electric field lines results in anincreased impedance section, thus providing a means of compensation forthe impedance discontinuity and reduction of wave reflection.

Referring now to FIG. 4, the structure is similar to that shown in FIG.1 except that a conductive insert 76 has been added to the cavity 74formed by the inside surface of sleeve 48. The insert 76 is formed witha concave surface 77 which is generally in the form of a portion of asphere and this portion, as shown in FIG. 4 fits over the insulationcovering 14 where it has been reduced in thicknes. As before, the airspace between the Teflon covering 14 and the conductive boundary 77 ofthe air space compensates for the change in impedance caused bystretching the insulation. A fiat spring 78 may be added to the insert75 in order that the closure plug 54 may retain the insert in conductivecontact with the cylindrical body 27 at all times. In this embodiment,as illustrated in FIG. 4, compensation is achieved in a differentmanner, viz., the electric field lines in the region of the bendterminate on the concave surface of the insert.

While there have been described herein what are at present consideredpreferred embodiments of the invention, it will be obvious to thoseskilled in the art that many modifications and changes may be madetherein without departing from the essence of the invention. It istherefore to be understood that the exemplary embodiments areillustrative and not restrictive of the invention.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:

1. An angularconnector for joining two sections of a concentricconductor comprising a single central conductor with end contactportions and formed with an angular bend covered with solid insulationbetween its contact portions, a main tubular body having a bore toreceive one end of the insulation and having a first terminal portion toreceive another conductor, an inner conductive extension of said mainbody, axially aligned therewith, and enclosing the bend portion of thecentral conductor and its insulation covering, conductive closure meansat the outer end of said extension, said extension and said closuremeans defining an air space adjoining the insulation covering on theconvex bend portion, a conductive insert positioned in said space andformed with a concave surface adjacent to the convex surface of theinsulation at its bent portion for providing a restricted air spacewhich compensates for the change in impedance due to the reducedthickness of solid insulation at the bend, said extensionhaving a sidewall opening and a conductive tubular extension secured in the openingat an angle to the main tubular body for supporting the other end of thecentral conductor and its insulation and for forming a second terminalportion.

2. A connector as claimed in claim 1 wherein said concave surface in theinsert is formed with the shape of an ellipse.

3. A connector as claimed in claim 1 wherein said insert includes edgeportions bordering the concave space which are substantially adjoiningthe insulation on the central conductor.

4. A connector as claimed in claim 1 wherein said insert is providedwith a resilient means for holding at least one edge portion inconductive contact with the main tubular body.

References Cited UNITED STATES PATENTS 2,754,487 7/1956 Carr et al.339--102 2,755,331 7/1956 Melcher 174-87 3,432,798 3/ 1969 Brishka.

RICHARD E. MOORE, Primary Examiner I. H. McGLYNN, Assistant Examiner

